Spreading signal generating method, generating device, receiving method and receiving device

ABSTRACT

The application relates to a spreading signal generating method, generating device, receiving method and receiving device. The spreading signal generating method comprises: generating a first spreading signal component and a second spreading signal component, wherein the first spreading signal component and the second spreading signal component each comprise a spreading code and a binary subcarrier, the spreading code of the first spreading signal component is the same as the spreading code of the second spreading signal component, the binary subcarrier of the first spreading signal component is different from the binary subcarrier of the second spreading signal component; and modulating the first spreading signal component and the second spreading signal component with radio frequency (RF) carriers so as to generate the spreading signal, where a phase of RF carrier for modulating the first spreading signal component is different from a phase of RF carrier for modulating the second spreading signal component.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to (is a continuation of) U.S.patent application Ser. No. 14/436,456 filed Apr. 16, 2015 entitled“Spreading Signal Generating Method, Generating Device, Receiving MethodAnd Receiving Device”; which in turn claims priority to (is a USNational Stage Filing of) PCT Application No. PCT/CN2014/093023 filedDec. 4, 2014 entitled “Spreading Signal Generating Method, GeneratingDevice, Receiving Method and Receiving Device”. The aforementioned PCTapplication claims priority to Chinese Patent Application No.201310655408.8 filed Dec. 6, 2013. The entirety of each of the threeaforementioned references is incorporated herein by reference for allpurposes.

TECHNICAL FIELD

The application relates to the field of spreading signal generatingmethod, generating device, receiving method and receiving device.

BACKGROUND OF THE INVENTION

Direct Sequence Spread Spectrum (DSSS) technique has widely used in thesignal of Global Navigation Satellite System (GNSS), in order to enableaccurate ranging through using the frequent phase reversal of spreadingcode and to achieve the good performance in multiple access, and that inanti-multipath and anti-interference. It has been found that sharing thelimited frequency band of GNSS among various GNSS signals is difficult.Hence, there exists a need in the are for advanced approaches.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a flowchart of a spreading signal generating methodaccording to an embodiment of the present application.

FIG. 2 illustrates a schematic block diagram of a spreading signalgenerating device according to an embodiment of the present application.

FIG. 3 illustrates a schematic block diagram of a spreading signalgenerating device according to another embodiment of the presentapplication.

FIG. 4 illustrates a schematic block diagram of a spreading signalreceiver according to an embodiment of the present application.

FIG. 5 illustrates a schematic diagram of an implementation of aspreading signal receiver according to an embodiment of the presentapplication.

FIG. 6 illustrates a flowchart of a spreading signal receiving methodaccording to an embodiment of the present application.

BRIEF SUMMARY OF THE INVENTION

The application relates to the field of spreading signal generatingmethod, generating device, receiving method and receiving device.

Some embodiments of the present invention provide a spreading signalgenerating method is disclosed, which includes: generating a firstspreading signal component and a second spreading signal component,wherein the first spreading signal component and the second spreadingsignal component each comprise a spreading code and a binary subcarrier,the spreading code of the first spreading signal component is the sameas the spreading code of the second spreading signal component, thebinary subcarrier of the first spreading signal component is differentfrom the binary subcarrier of the second spreading signal component; andmodulating the first spreading signal component and the second spreadingsignal component with radio frequency (RF) carriers so as to generatethe spreading signal, wherein a phase of RF carrier for modulating thefirst spreading signal component is different from a phase of RF carrierfor modulating the second spreading signal component, and the spreadingsignal generated is:S _(RF) =S ₁·cos(ω_(RF) t)+S ₂·cos(ω_(RF) t+θ)S ₁ =A ₁ ·c(t)·q ₁(t)·d(t)S ₂ =A ₂ ·c(t)·q ₂(t)·d(t),where S_(RF) stands for the spreading signal, S₁ and S₂ stand for thefirst spreading signal component and the second spreading signalcomponent respectively, A₁ and A₂ stand for an amplitude of S₁ and anamplitude of S₂ respectively, c(t) stands for the spreading code of S₁and S₂, q₁(t) and q₂(t) stand for the binary subcarrier of S₁ and thebinary subcarrier of S₂, d(t) stands for a data message, ω_(RF) standsfor an angular frequency of RF carrier, and θ stands for a phasedifference between the phase of RF carrier for modulating S₁ and thephase of RF carrier for modulating S₂.

DETAILED DESCRIPTION

Hereinafter, with reference to the appended drawings, a detaileddescription on the spreading signal generating method, generatingdevice, receiving method and receiving device disclosed in theapplication will be presented. For simplicity, in the description of theembodiments of the present application, the same or similar referencenumeral is used for the same or similar device.

It has been determined that sharing a limited frequency band of GNSSamong various GNSS signals while improving the ranging accuracy andanti-interference performance of signals, it is useful to use new signalmodulation techniques. Binary Offset Carrier (BOC) modulation is one ofsuch examples, where a signal is multiplied by a square-wave subcarrierbased on the DSSS modulation of rectangular non-return-to-zero spreadingcode chip. In general, BOC modulation has two parameters: a subcarrierrate f_(s) and a spreading sequence rate f_(c), where f_(s)≧f_(c).Therefore, a specific BOC modulation can be denoted via BOC(f_(s),f_(c)). In the context of GNSS, a more simple notation is BOC(m,n),where f_(s) and f_(c) are normalized with 1.023 MHz, that is,m=f_(s)/1.023 MHz and n=f_(c)/1.023 MHz. In addition, there emergevarious multiplexed BOC modulation techniques, such as Time-MultiplexedBinary Offset Carrier (TMBOC) modulation, and Composite Binary OffsetCarrier (CBOC) modulation.

Some embodiments of the present inventions provide a spreading signalgenerating method, generating device, receiving method and receivingdevice.

In some instances of the aforementioned embodiments, a spreading signalgenerating method is disclosed, which comprises: generating a firstspreading signal component and a second spreading signal component,wherein the first spreading signal component and the second spreadingsignal component each comprise a spreading code and a binary subcarrier,the spreading code of the first spreading signal component is the sameas the spreading code of the second spreading signal component, thebinary subcarrier of the first spreading signal component is differentfrom the binary subcarrier of the second spreading signal component; andmodulating the first spreading signal component and the second spreadingsignal component with radio frequency (RF) carriers so as to generatethe spreading signal, wherein a phase of RF carrier for modulating thefirst spreading signal component is different from a phase of RF carrierfor modulating the second spreading signal component, and the spreadingsignal generated is:S _(RF) =S ₁·cos(ω_(RF) t)+S ₂·cos(ω_(RF) t+θ)S ₁ =A ₁ ·c(t)·q ₁(t)·d(t)S ₂ =A ₂ ·c(t)·q ₂(t)·d(t),where S_(RF) stands for the spreading signal, S₁ and S₂ stand for thefirst spreading signal component and the second spreading signalcomponent respectively, A₁ and A₂ stand for an amplitude of S₁ and anamplitude of S₂ respectively, c(t) stands for the spreading code of S₁and S₂, q₁(t) and q₂(t) stand for the binary subcarrier of S₁ and thebinary subcarrier of S₂, d(t) stands for a data message, ω_(RF) standsfor an angular frequency of RF carrier, and θ stands for a phasedifference between the phase of RF carrier for modulating S₁ and thephase of RF carrier for modulating S₂.

In various instances of the aforementioned embodiments, a spreadingsignal generating device is disclosed, which comprises: a spreadingsignal component generating unit to generate a first spreading signalcomponent and a second spreading signal component, wherein the firstspreading signal component and the second spreading signal componenteach comprises a spreading code and a binary subcarrier, the spreadingcode of the first spreading signal component is the same as thespreading code of the second spreading signal component, the binarysubcarrier of the first spreading signal component is different from thebinary subcarrier of the second spreading signal component; and aspreading signal generating unit to modulate the first spreading signalcomponent and the second spreading signal component with RF carriers soas to generate the spreading signal, wherein a phase of RF carrier formodulating the first spreading signal component is different from aphase of RF carrier for modulating the second spreading signalcomponent, and the spreading signal generating unit generates thespreading signal with the following equations:S _(RF) =S ₁·cos(ω_(RF) t)+S ₂·cos(ω_(RF) t+θ)S ₁ =A ₁ ·c(t)·q ₁(t)·d(t)S ₂ =A ₂ ·c(t)·q ₂(t)·d(t)where S_(RF) stands for the spreading signal, S₁ and S₂ stand for thefirst spreading signal component and the second spreading signalcomponent respectively, A₁ and A₂ stand for an amplitude of S₁ and anamplitude of S₂ respectively, c(t) stands for the spreading code of S₁and S₂, q₁(t) and q₂(t) stand for the binary subcarrier of S₁ and thebinary subcarrier of S₂ respectively, d(t) stands for a data message,ω_(RF) stands for an angular frequency of RF carrier, θ stands for aphase difference between the phase of RF carrier for modulating S₁ andthe phase of RF carrier for modulating S₂.

In one or more instances of the aforementioned embodiments, a method forreceiving a spreading signal is disclosed, which comprises: generating alocal replica of spreading code of the spreading signal; generating alocal replica of binary subcarrier of the first spreading signalcomponent and a local replica of binary subcarrier of the secondspreading signal component; generating a local carrier based on a phasedifference between a phase of RF carrier for modulating the firstspreading signal component and a phase of RF carrier for modulating thesecond spreading signal component; calculating a coherent integrationfor the spreading signal received, and calculating a linear combinationof results of the integration, based on the local carrier, the localreplica of spreading code, the local replica of binary subcarrier of thefirst spreading signal component and the local replica of binarysubcarrier of the second spreading signal component generated, so as toobtain an integrated in-phase channel component and an integratedquadrature-phase channel component.

In some instances of the aforementioned embodiments, a spreading signalreceiver is disclosed, which comprises: a baseband signal generatingunit to generate a local replica of spreading code of the spreadingsignal and to generate a local replica of binary subcarrier of a firstspreading signal component and a local replica of binary subcarrier of asecond spreading signal component; a local carrier generating unit togenerate the local carrier based on a phase difference between a phaseof RF carrier for modulating the first spreading signal component and aphase of RF carrier for modulating the second spreading signalcomponent; and a calculating unit to calculate a coherent integrationfor the spreading signal received, and calculating a linear combinationof results of the integration, based on the local carrier, the localreplica of spreading code, the local replica of binary subcarrier of thefirst spreading signal component and the local replica of binarysubcarrier of the second spreading signal component generated, so as toobtain an integrated in-phase channel component and an integratedquadrature-phase channel component.

FIG. 1 illustrates a flowchart of a spreading signal generating methodfor generating a spreading signal S_(RF) according to an embodiment ofthe present application.

In Step 110, a first spreading signal component S₁ and a secondspreading signal component S₂ are generated, wherein the first spreadingsignal component S₁ and the second spreading signal component S₂ eachcomprise a spreading code and a binary subcarrier. The spreading code ofthe first spreading signal component S₁ is the same as the spreadingcode of the second spreading signal component S₂, and the binarysubcarrier of the first spreading signal component S₁ is different fromthe binary subcarrier of the second spreading signal component S₂.

In Step 120, the first spreading signal component S₁ and the secondspreading signal component S₂ are modulated with RF carriers so as togenerate the spreading signal S_(RF), wherein a phase of RF carrier formodulating the first spreading signal component S₁ is different from aphase of RF carrier for modulating the second spreading signal componentS₂.

The two spreading signal components each comprise the spreading code andthe binary subcarrier are modulated with two different carrier phasesrespectively, enabling the multiplex of spreading signal components.

The spreading signal S_(RF) generated in Step 120 is expressed as:S _(RF) =S ₁·cos(ω_(RF) t)+S ₂·cos(ω_(RF) t+θ),where S ₁ =A ₁ ·c(t)·q ₁(t)·d(t), andS ₂ =A ₂ ·c(t)·q ₂(t)·d(t),wherein S₁ and S₂ stand for the first spreading signal component and thesecond spreading signal component respectively, A₁ and A₂ stand for anamplitude of S₁ and an amplitude of S₂ respectively, c(t) stands for thespreading code of S₁ and S₂, q₁(t) and q₂(t) stand for the binarysubcarrier of S₁ and the binary subcarrier of S₂ respectively, d(t)stands for a data message, ω_(RF) stands for an angular frequency of RFcarrier, and θ stands for a phase difference between the phase of RFcarrier for modulating S₁ and the phase of RF carrier for modulating S₂.

According to an embodiment of the present application, the binarysubcarrier is a binary coded symbol (BCS) subcarrier. For example, thesubcarrier of the first spreading signal component S₁ can be BCS([1 1 11-1 1 1 1 1], 1), and the subcarrier of the second spreading signalcomponent S₂ can be BCS([1 1 1 1 1-1 1 1 1 1 1], 1), among others. Ascan be appreciated by those skilled in the art, the BCS subcarrierherein is only for exemplary illustration, and the binary subcarrier ofspreading signal component can be any form of BCS subcarrier.

According to another embodiment of the present application, the binarysubcarrier is a binary offset carrier (BOC) subcarrier, i.e., BOC(m, n),wherein m is the result of the square-wave subcarrier frequency f_(s) ofthe BOC component normalized with 1.023 MHz, that is, m=f_(s)/1.023 MHz;n is the result of the spreading code c(t) frequency f_(c) of the BOCsignal normalized with 1.023 MHz. For example, the subcarrier of thefirst spreading signal component S₁ can be BOC(1, 1), and the subcarrierof the second spreading signal component S₂ can be BOC(6, 1). As can beappreciated by those skilled in the art, BOC(1, 1) and BOC(6, 1) hereinare only for exemplary illustration, and the binary subcarrier ofspreading signal component can be any form of BOC subcarrier.

When the binary subcarrier is a BOC subcarrier, the spreading signalcomponents S₁ and S₂ are BOC signals. As can be appreciated, in thiscase the two BOC signals are multiplexed. According to the BOC multiplexmethod of the present embodiment, the two signal components aremodulated on different phases of the carrier respectively. With theembodiment, the proportion of an inter-modulation component between twodifferent BOC signal components among the total signal can be flexiblyadjusted.

As can be appreciated by those skilled in the art, the acquisition,tracking, demodulation and anti-multipath and other performances of asignal at receiving are in close relation to the spectralcharacteristics of the signal. With regard to the multiplexed BOC signalof the present embodiment, the acquisition, tracking, demodulation andanti-multipath performances at receiving can be influenced by the amountof the inter-modulation component between the two signal components.

According to an embodiment of the present application, a phasedifference θ can be further set so as to adjust the inter-modulationcomponent between the first spreading signal component S₁ and the secondspreading signal component S₂. By means of setting the carrier phaserelationship of the two signal components, characteristics of the signalto be transmitted can be adjusted so as to optimize the acquisition,tracking, demodulation and anti-multipath performances at receiving, forsatisfying specific requirements.

According to the present embodiment, a baseband signal can be expressedas:S _(BB)(t)=S ₁(t)+S ₂(t)e ^(jθ).in this case, the auto-correlation function of the baseband signal isR(τ)=A ₁ ² R ₁(τ)+A ₂ ² R ₂(τ)+2A ₁ A ₂ R _(c)(τ)cos θ,where R₁ and R₂ are an auto-correlation function of c(t)q₁(t) and anauto-correlation function of c(t)q₂(t) respectively, and R_(c)(τ) is across-correlation function of c(t)q₁(t) and c(t)q₂(t). As can be seen,in addition to the auto-correlation function of the first spreadingsignal component and the auto-correlation function of the secondspreading signal component, the cross-correlation function of the firstspreading signal component and the second spreading signal component,i.e., the aforementioned inter-modulation component, is also included inthe auto-correlation function of the baseband signal.

cos θ can be configured to be any value between −1 and +1 by setting avalue of the phase difference θ, such that the amount of theinter-modulation component can be adjusted.

According to an embodiment of the present application, the value of thephase difference θ can be determined based on a demodulation performanceindex η and a tracking performance index β as required at the receivingof the spreading signal. The demodulation performance index η at thereceiving of the spreading signal depicts the power loss of thespreading signal introduced due to the transmitter filtering, whichdirectly influences the correlator output signal to noise ratio (SNR) ofthe receiver. The tracking performance index β refers to the root meansquare (RMS) bandwidth of the spreading signal after the transmitterfiltering, which directly influences the tracking loop error under thethermal noise and multipath.

For example, the demodulation performance index η and the trackingperformance index β can be expressed as the following equations:

${\eta(\theta)} = \frac{\int_{B\; W}{\int_{- \infty}^{+ \infty}{( {{A_{1}^{2}{R_{1}(\tau)}} + {A_{2}^{2}{R_{2}(\tau)}} + {2A_{1}A_{2}{R_{c}(\tau)}\cos\;\theta}} ){\mathbb{e}}^{{- {j2\pi}}\; f\;\tau}{\mathbb{d}\tau}\; d\; f}}}{\int_{- \infty}^{+ \infty}{\int_{- \infty}^{+ \infty}{( {{A_{1}^{2}{R_{1}(\tau)}} + {A_{2}^{2}{R_{2}(\tau)}} + {2A_{1}A_{2}{R_{c}(\tau)}\cos\;\theta}} ){\mathbb{e}}^{{- {j2\pi}}\; f\;\tau}{\mathbb{d}\tau}\; d\; f}}}$${\beta(\theta)} = ( \frac{\int_{B\; W}{f^{2}{\int_{- \infty}^{+ \infty}{( {{A_{1}^{2}{R_{1}(\tau)}} + {A_{2}^{2}{R_{2}(\tau)}} + {2\; A_{1}A_{2}{R_{c}(\tau)}\cos\;\theta}} ){\mathbb{e}}^{{- j}\; 2\pi\; f\;\tau}{\mathbb{d}\tau}\; d\; f}}}}{\int_{- \infty}^{+ \infty}{\int_{- \infty}^{+ \infty}{( {{A_{1}^{2}{R_{1}(\tau)}} + {A_{2}^{2}{R_{2}(\tau)}} + {2\; A_{1}A_{2}{R_{c}(\tau)}\cos\;\theta}} ){\mathbb{e}}^{{- j}\; 2\pi\; f\;\tau}{\mathbb{d}\tau}\; d\; f}}} )^{1/2}$where BW is a signal transmitter bandwidth, n₀ is a double-sided powerspectral density of the white Gaussian noise (GWN), A₁ and A₂ stand foran amplitude of the first spreading signal component S₁ and an amplitudeof the second spreading signal component S₂ respectively, R₁ stands foran auto-correlation function of c(t)q₁(t), R₂ stands for anauto-correlation function of c(t)q₂(t), and R_(c)(τ) is across-correlation function of c(t)q₁(t) and c(t)q₂(t).

According to the requirement of accuracy, by means of traversing all thepossible values of the phase difference θ among the {θ_(k), k=1, 2, . .. , N} with a certain step, a set of corresponding demodulationperformance indices {η_(k), k=1, 2, . . . , N} and a set ofcorresponding tracking performance indices {β_(k), k=1, 2, . . . , N}can be obtained, wherein the number N of the traversing of the phasedifference θ is determined by the required accuracy. As can beunderstood by those skilled in the art, the anti-multipath performanceof signal is related to the tracking performance index β. According torequirement for demodulation performance, tracking performance andanti-multipath performance in the signal design, a pair of trackingperformance index and demodulation performance index (β_(k-opt),η_(k-opt)) can be selected among the {η_(k), k=1, 2, . . . } and {θ_(k),k=1, 2, . . . } to satisfy the requirements, and then the value of thephase difference θ will be set as θ_(k-opt).

According to an embodiment of the present application, the phasedifference θ can be set as

${\pm \frac{\pi}{2}},$so as to adjust the inter-modulation component between the firstspreading signal component S₁ and the second spreading signal componentS₂ as being zero.

For example, for a BOC subcarrier, when the phase difference θ is

${\pm \frac{\pi}{2}},$the baseband signal can be expressed as:S _(BB)(t)=S ₁(t)±jS ₂(t), andthe auto-correlation function of the baseband signal isR(τ)=A ₁ ² R ₁(τ)+A ₂ ² R ₂(τ).

As can be seen, when the phase difference θ is

${\pm \frac{\pi}{2}},$no inter-modulation component is included in the auto-correlationfunction of the baseband signal. In this regard, different data messagesare allowed to be modulated on the two signal components, so as toincrease the information quantity to be transmitted by the signal.

FIG. 2 illustrates a schematic block diagram of a spreading signalgenerating device according to an embodiment of the present application.As shown, a spreading signal generating device 200 comprises a spreadingsignal component generating unit 210 and a spreading signal generatingunit 220.

The spreading signal component generating unit 210 generates the firstspreading signal component and the second spreading signal component,wherein the first spreading signal component and the second spreadingsignal component each comprise a spreading code and a binary subcarrier.The spreading code of the first spreading signal component is the sameas the spreading code of the second spreading signal component, thebinary subcarrier of the first spreading signal component is differentfrom the binary subcarrier of the second spreading signal component.

The spreading signal generating unit 220 modulates the first spreadingsignal component and the second spreading signal component with RFcarriers so as to generate a spreading signal, wherein a phase of RFcarrier for modulating the first spreading signal component is differentfrom a phase of RF carrier for modulating the second spreading signalcomponent.

According to an embodiment, a spreading signal generating unit 220generates a spreading signal S_(RF) with the following equations:S _(RF) =S ₁·cos(ω_(RF) t)+S ₂·cos(ω_(RF) t+θ),where S ₁ =A ₁ ·c(t)·q ₁(t)·d(t), andS ₂ =A ₂ ·c(t)·q ₂(t)·d(t),wherein S₁ and S₂ stand for the first spreading signal component and thesecond spreading signal component respectively, A₁ and A₂ stand for anamplitude of S₁ and an amplitude of S₂ respectively, c(t) stands for thespreading code of S₁ and S₂, q₁(t) and q₂(t) stand for the binarysubcarrier of S₁ and the binary subcarrier of S₂ respectively, d(t)stands for a data message, ω_(RF) stands for an angular frequency of RFcarrier, and θ stands for a phase difference between the phase of RFcarrier for modulating S₁ and the phase of RF carrier for modulating S₂.

FIG. 3 illustrates a schematic block diagram of a spreading signalgenerating device according to another embodiment of the presentapplication. As shown, a spreading signal generating unit 220 of aspreading signal generating device 200 can further comprise a phasedifference setting module 221 and a signal generating module 222. Thephase difference setting module 221 sets said phase difference betweenthe phase of RF carrier for modulating the first spreading signalcomponent S₁ and the phase of RF carrier for modulating the secondspreading signal component S₂, so as to adjust the inter-modulationcomponent between the first spreading signal component S₁ and the secondspreading signal component S₂. The signal generating module 222generates the spreading signal S_(RF) based on the phase difference θset by the phase difference setting module 221. For example, based onthe phase difference θ set by the phase difference setting module 221,the signal generating module 222 generates the spreading signal S_(RF)with the following equations:S _(RF) =S ₁·cos(ω_(RF) t)+S ₂·cos(ω_(RF) t+θ),where S ₁ =A ₁ ·c(t)·q ₁(t)·d(t), andS ₂ =A ₂ ·c(t)·q ₂(t)·d(t),wherein S₁ and S₂ stand for the first spreading signal component and thesecond spreading signal component respectively, A₁ and A₂ stand for anamplitude of S₁ and an amplitude of S₂ respectively, c(t) stands for thespreading code of S₁ and S₂, q₁(t) and q₂(t) stand for the binarysubcarrier of S₁ and the binary subcarrier of S₂ respectively, d(t)stands for a data message, ω_(RF) stands for an angular frequency of RFcarrier, and θ stands for a phase difference between the phase of RFcarrier for modulating S₁ and the phase of RF carrier for modulating S₂.

According to an embodiment, a phase difference setting module 221determines the value of the phase difference θ based on a demodulationperformance index and a tracking performance index as required at thereceiving of the spreading signal.

According to an embodiment, a phase difference setting module 221 canset the RF carrier phase difference θ between the first spreading signalcomponent S₁ and the second spreading signal component S₂ as

${\pm \frac{\pi}{2}},$so as to adjust the inter-modulation component between the firstspreading signal component S₁ and the second spreading signal componentS₂ as being zero. In addition, the phase difference setting module 221may set the phase difference θ to be any value and thereby cos θ can beof any value between −1 and +1, such that the amount of theinter-modulation component between the first spreading signal componentS₁ and the second spreading signal component S₂ can be changed.

The embodiments of the present application described as above are mainlyinvolved with the transmission side, that is, with spreading signalgenerating methods and generating devices. In addition, embodiments ofthe present application also relate to signals generated through suchspreading signal generating methods and by generating devices as thosedescribed above.

Moreover, as can be appreciated by those skilled in the art, conversesystems, methods, and devices can be applied so as to receive andprocess spreading signals generated in the embodiments of the presentapplication. Therefore, the embodiments of the present application alsorelate to systems, methods, and devices for processing, for example,spreading signals as described above.

FIG. 4 illustrates a schematic block diagram of a spreading signalreceiver according to an embodiment of the present application. Asshown, a receiver 300 comprises a baseband signal generating unit 310, alocal carrier generating unit 320, and a calculating unit 330. Thereceiver 300 can be used to process a spreading signal S_(RF) received.

The baseband signal generating unit 310 generates a local replica ĉ(t)of spreading code of the spreading signal S_(RF), a local replica{circumflex over (q)}₁(t) of binary subcarrier of a first spreadingsignal component and a local replica {circumflex over (q)}₂(t) of binarysubcarrier of a second spreading signal component.

The local carrier generating unit 320 generates a local carrier based ona phase difference θ between a phase of RF carrier for modulating thefirst spreading signal component and a phase of RF carrier formodulating the second spreading signal component.

Based on the local carrier generated by the local carrier generatingunit 320, as well as the local replica ĉ(t) of spreading code, the localreplica {circumflex over (q)}₁(t) of binary subcarrier of the firstspreading signal component and the local replica {circumflex over(q)}₂(t) of binary subcarrier of the second spreading signal componentgenerated by the baseband signal generating unit 310, the calculatingunit 330 calculates a coherent integration for the spreading signalS_(RF) received, and also calculates a linear combination of results ofthe integration, so as to obtain an integrated in-phase channelcomponent I and an integrated quadrature-phase channel component Q.

FIG. 5 illustrates a schematic diagram of an implementation of aspreading signal receiver according to an embodiment of the presentapplication.

As shown in FIG. 5, a baseband signal generating unit 310 furthercomprises a local spreading code replica generating module 311 and alocal subcarrier replica generating module 312. The local spreading codereplica generating module 311 generates a local replica ĉ(t) ofspreading code of a spreading signal S_(RF). The local subcarrierreplica generating module 312 generates a local replica {circumflex over(q)}₁(t) of binary subcarrier of a first spreading signal component anda local replica {circumflex over (q)}₂(t) of binary subcarrier of asecond spreading signal component.

The local carrier generating unit 320 further comprises a local carriergenerating module 321. Based on a phase difference θ between a phase ofRF carrier for modulating the first spreading signal component and aphase of RF carrier for modulating the second spreading signalcomponent, the local carrier generating module 321 generates localcarriers cos({circumflex over (ω)}t), sin({circumflex over (ω)}t),cos({circumflex over (ω)}t+θ), sin({circumflex over (ω)}t+θ), wherein{circumflex over (ω)} stands for a demodulation angular frequency oflocal carrier. As can be appreciated, if a spreading signal received isdemodulated immediately, then {circumflex over (ω)}=ω_(RF); if aspreading signal is demodulated after a carrier of the spreading signalis converted to an intermediate frequency via a down-converter, then{circumflex over (ω)}≦ω_(RF), where {circumflex over (ω)} is the carrierintermediate frequency via the down-converter.

The calculating unit 330 further comprises a coherent integrationcalculating module 331 and a linear combination calculating module 332.

The coherent integration calculating module 331 calculates a coherentintegration for the spreading signal S_(RF) received based on the localcarriers cos({circumflex over (ω)}t), sin({circumflex over (ω)}t),cos({circumflex over (ω)}t+θ), sin({circumflex over (ω)}t+θ) generatedby the local carrier generating unit 320, and on the local replica ĉ(t)of spreading code, the local replica {circumflex over (q)}₁(t) of binarysubcarrier of the first spreading signal component and the local replica{circumflex over (q)}₂(t) of binary subcarrier of the second spreadingsignal component generated by the baseband signal generating unit 310.The coherent integration calculation can be expressed specifically as:L ₁=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₁(t)cos({circumflex over (ω)}t)dtL ₂=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₁(t)sin({circumflex over (ω)}t)dtL ₃=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₂(t)cos({circumflex over (ω)}t+θ)dtL ₄=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₂(t)sin({circumflex over (ω)}t+θ)dtwhere {tilde over (S)}_(RF)(t) stands for the spreading signal received,ĉ(t) stands for the local replica of spreading code, {circumflex over(q)}₁(t) and {circumflex over (q)}₂(t) stand for the local replica ofbinary subcarrier of the first spreading signal component and the localreplica of binary subcarrier of the second spreading signal componentrespectively, {circumflex over (ω)} stands for an angular frequency oflocal carrier; t₁ is a starting time for coherent integration, T_(coh)is a duration for integration; Ã₁ and Ã₂ are a first weightingcoefficient and a second weighting coefficient respectively, whereÃ₁:Ã₂=A₁:A₂; L₁, L₂, L₃, L₄ are results of the coherent integration; andI and Q are an integrated in-phase channel component and an integratedquadrature-phase channel component respectively.

The linear combination calculating module 332 calculates a linearcombination of results calculated by the coherent integrationcalculating module 331, so as to obtain an integrated in-phase channelcomponent I and an integrated quadrature-phase channel component Q,specifically, with:I=Ã ₁ L ₁ +Ã ₂ L ₃Q=−Ã ₁ L ₂ −Ã ₂ L ₄where Ã₁ and Ã₂ are the first weighting coefficient and the secondweighting coefficient respectively, a ratio between which equals to aratio between an amplitude A₁ of spreading signal component S₁ and anamplitude A₂ of spreading signal component S₂ at the generation of thespreading signal, that is, Ã₁:Ã₂=A₁:A₂.

According to an embodiment of the present application, as shown in FIG.5, a receiver 300 may further comprise a processing unit 340, whichcarries out the carrier synchronization, code timing synchronization,data demodulation, measurement of the ranging code phase and carrierphase based on the integrated in-phase channel component and theintegrated quadrature-phase channel component obtained. As can beappreciated by those skilled in the art, after the integrated in-phasechannel component I and the integrated quadrature-phase channelcomponent Q are obtained in the receiver, functions such as the carriersynchronization, code timing synchronization, data demodulation,measurement of the ranging code phase and carrier phase and so oncarried out by the processing unit are in a manner similar to those inthe prior art, details of which hence will not be described herein.

FIG. 6 illustrates a flowchart of a spreading signal receiving methodaccording to an embodiment of the present application. As shown, in Step410, a local replica of spreading code of a spreading signal isgenerated.

In Step 420, a local replica of binary subcarrier of a first spreadingsignal component and a local replica of binary subcarrier of a secondspreading signal component are generated.

In Step 430, a local carrier is generated based on a phase differencebetween a phase of RF carrier for modulating the first spreading signalcomponent and a phase of RF carrier for modulating the second spreadingsignal component.

In Step 440, the coherent integration for the spreading signal receivedand the linear combination of results of the integration are calculated,based on the local carrier, the local replica of spreading code, thelocal replica of binary subcarrier of the first spreading signalcomponent and the local replica of binary subcarrier of the secondspreading signal component generated, so as to obtain an integratedin-phase channel component and an integrated quadrature-phase channelcomponent.

According to an embodiment of the present application, the coherentintegration can be calculated in Step 440 with the following equations:L ₁=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₁(t)cos({circumflex over (ω)}t)dtL ₂=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₁(t)sin({circumflex over (ω)}t)dtL ₃=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₂(t)cos({circumflex over (ω)}t+θ)dt,L ₄=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₂(t)sin({circumflex over (ω)}t+θ)dtand the linear combination can be calculated with the followingequations:I=Â ₁ L ₁ +Â ₂ L ₃,Q=−Â ₁ L ₂ −Â ₂ L ₄where {tilde over (S)}_(RF)(t) is a spreading signal received, ĉ(t) is alocal replica of spreading code, {circumflex over (q)}₁(t) and{circumflex over (q)}₂(t) are a local replica of binary subcarrier of afirst spreading signal component and a local replica of binarysubcarrier of a second spreading signal component respectively,{circumflex over (ω)} is an angular frequency of local carrier; t₁ is astarting time for coherent integration, T_(coh) is a duration forintegration; Ã₁ and Ã₂ are a first weighting coefficient and a secondweighting coefficient respectively, where Ã₁:Ã₂=A₁:A₂; L₁, L₂, L₃, L₄stand for results of the coherent integration; and I and Q are anintegrated in-phase channel component and an integrated quadrature-phasechannel component respectively.

According to an embodiment of the present application, a spreadingsignal receiving method can further comprise: carrying out the carriersynchronization, code timing synchronization, data demodulation,measurement of the ranging code phase and carrier phase, based on theintegrated in-phase channel component and the integratedquadrature-phase channel component obtained. As can be appreciated,those skilled in the art can employ various manners in the prior art forcarrying out the carrier synchronization, code timing synchronization,data demodulation, measurement of the ranging code phase and carrierphase, based on the integrated in-phase channel component and theintegrated quadrature-phase channel component.

Embodiments of the present application can be implemented in the form ofhardware, software or the combination thereof. According to an aspect ofthe present application, a program is provided comprising executableinstructions to implement the spreading signal generating method,generating device, spreading signal receiving method, receiving deviceaccording to embodiments of the present application. In addition, theprogram can be stored in a storage of any form, such as optical ormagnetic readable media, chip, ROM, PROM, or volatile or non-volatilememory device. According to an example of an embodiment of the presentapplication, a machine-readable storage is provided for storing theprogram.

While various embodiments of the present application have been describedabove referring to the drawings, it should be understood that they havebeen presented by way of example only, and not limitation. It will beapparent to those skilled in the art that various changes in form anddetail can be made therein without departing from the spirit and scopeof the invention.

What is claimed is:
 1. A spreading signal generating method, comprising:using a spreading signal component generating circuit to generate afirst spreading signal component and a second spreading signalcomponent, wherein the first spreading signal component and the secondspreading signal component each includes a spreading code and a binarysubcarrier, wherein the spreading code of the first spreading signalcomponent is the same as the spreading code of the second spreadingsignal component, and the binary subcarrier of the first spreadingsignal component is different from the binary subcarrier of the secondspreading signal component; modulating the first spreading signalcomponent with a first RF carrier and the second spreading signalcomponent with a second RF carrier so as to generate a unified spreadingsignal, wherein a phase of the first RF carrier is different from aphase of the second RF carrier, wherein a phase difference between thephase of the first RF carrier and the phase of the second RF carrier isset to adjust an inter-modulation component between the first spreadingsignal component and the second spreading signal component; and whereinthe unified spreading signal generated is:S _(RF) =S ₁·cos(ω_(RF) t)+S ₂·cos(ω_(RF) t+θ)S ₁ =A ₁ ·c(t)·q ₁(t)·d(t)S ₂ =A ₂ ·c(t)·q ₂(t)·d(t), where S_(RF) stands for the spreadingsignal, S₁ and S₂ stand for the first spreading signal component and thesecond spreading signal component respectively, A₁ and A₂ stand for anamplitude of S₁ and an amplitude of S₂ respectively, c(t) stands for thespreading code of S₁ and S₂, q₁(t) and q₂(t) stand for the binarysubcarrier of S₁ and the binary subcarrier of S₂ respectively, d(t)stands for a data message, ω_(RF) stands for an angular frequency of RFcarrier, and θ stands for a phase difference between the phase of thefirst RF carrier and the phase of the second RF carrier.
 2. The methodas claimed in claim 1, wherein the binary subcarrier is a binary codedsymbol BCS subcarrier.
 3. The method as claimed in claim 2, the methodfurther comprising: setting the phase difference θ as$\pm \frac{\pi}{2}$ so as to adjust the inter-modulation componentbetween the first spreading signal component S₁ and the second spreadingsignal component S₂ as being zero.
 4. The method as claimed in claim 1,wherein the binary subcarrier is a binary offset carrier BOC subcarrier.5. The method as claimed in claim 4, the method further comprising:setting the phase difference θ as $\pm \frac{\pi}{2}$ so as to adjustthe intern-modulation component between the first spreading signalcomponent S₁ and the second spreading signal component S₂ as being zero.6. The method as claimed in claim 1, further comprising: determining thevalue of the phase difference θ based on a demodulation performanceindex and a tracking performance index as required at the receiving ofthe spreading signal.
 7. The method as claimed in claim 6, furthercomprising: setting the phase difference θ as $\pm \frac{\pi}{2}$ so asto adjust the inter-modulation component between the first spreadingsignal component S₁ and the second spreading signal component S₂ asbeing zero.
 8. A method for receiving a spreading signal, the methodcomprising: generating a local replica of a spreading code of aspreading signal; generating a local replica of a binary subcarrier of afirst spreading signal component and a local replica of a binarysubcarrier of a second spreading signal component; generating a localcarrier based on the phase difference between a phase of an RF carrierfor modulating the first spreading signal component and a phase of an RFcarrier for modulating the second spreading signal component;calculating a coherent integration for the spreading signal received andcalculating a linear combination of results of the integration, based onthe local carrier, the local replica of spreading code, the localreplica of binary subcarrier of the first spreading signal component andthe local replica of binary subcarrier of the second spreading signalcomponent generated, so as to obtain an integrated in-phase channelcomponent and an integrated quadrature-phase channel component; andwherein the coherent integration is calculated with the followingequations:L ₁=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₁(t)cos({circumflex over (ω)}t)dtL ₂=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₁(t)sin({circumflex over (ω)}t)dtL ₃=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₂(t)cos({circumflex over (ω)}t+θ)dtL ₄=∫_(t) ₁ ^(t) ¹ ^(+T) ^(coh) {tilde over (S)} _(RF)(t){circumflexover (c)}(t){circumflex over (q)} ₂(t)sin({circumflex over (ω)}t+θ)dt,and the linear combination is calculated with the following equations:I=Â ₁ L ₁ +Â ₂ L ₃Q=−Â ₁ L ₂ −Â ₂ L ₄, where {tilde over (S)}_(RF)(t) stands for thespreading signal received, ĉ(t) is the local replica of spreading code,{circumflex over (q)}₁(t) and {circumflex over (q)}₂(t) are the localreplica of binary subcarrier of the first spreading signal component andthe local replica of binary subcarrier of the second spreading signalcomponent respectively, {circumflex over (ω)} is an angular frequency oflocal carrier; t₁ is a starting time for coherent integration, T_(coh)is a duration for integration; Ã₁ and Ã₂ are a first weightingcoefficient and a second weighting coefficient respectively, whereÃ₁:Ã₂=A₁:A₂; L₁, L₂, L₃, L₄ are results of the coherent integration; andI and Q are the integrated in-phase channel component and the integratedquadrature-phase channel component respectively.
 9. The method asclaimed in claim 8, further comprising: carrying out the carriersynchronization, code timing synchronization, data demodulation,measurement of the ranging code phase and carrier phase, based on theintegrated in-phase channel component and the integratedquadrature-phase channel component obtained.